Scientists Identify Possible New Substance With Highest Melting Point

JoshuaZ writes: Researchers from Brown University have tentatively identified an alloy of hafnium, nitrogen and carbon as having an expected melting point of about 7,460 degrees Fahrenheit (4120 Celsius). This exceeds that of the previous record-breaker, tantalum hafnium carbide, which melts at 7,128 F (3942 C). Its record stood for almost a century. At this point, the new alloy is still hypothetical, based on simulations, so the new record has not yet been confirmed by experiment. The study was published in Physical Review B (abstract), and a lay-summary is available at the Washington Post. If the simulations turn out to be correct, the new alloy may be useful in parts like jet engines, and the door will be opened to using similar simulations to search for substances with even higher melting points or with other exotic properties.

Comments

Probably not useful

[dj245]

If the simulations turn out to be correct, the new alloy may be useful in parts like jet engines, and the door will be opened to using similar simulations to search for substances with even higher melting points or with other exotic properties.

No, it won't. Materials for jet engines must be reasonably affordable, machinable or otherwise workable, and available in large quantities. I have about 4600 lbs [2086kg] of 422 stainless going through my shop right now for a single row of blades for one machine. They're big blades, but even for small blades, hundreds of pounds of material is common. An alloy of hafnium, nitrogen and carbon isn't going to be cheap enough for that to ever be feasible. It is probably a brittle material as well. Brittle materials and a high vibration environment don't mix.

Maybe you could apply it as a coating, but I'm not sure how that would be possible. Almost all coatings of this type require you to liquify or vaporize the coating material. Plus, you run into the same problem as before- a thin coating won't protect the base metal, and a thick one would be prohibitively expensive.

Re:Probably not useful

[EmperorArthur]

Hafnium is about a dollar / gram. Nitrogen and carbon are plentiful and relatively cheap. Is this dramatically more expensive than current high temp materials?

442 stainless steel is US $1500.00 / Ton from Alibaba. Assuming metric, that works out to $1.5/kg, or $0.0015/g.
Plus that $1/g is just for the raw Hafnium. Alloys like the one proposed here tend to be expensive, time consuming, and finicky to get right.

Then you get into the fact that producing Hafnium leaves pure Zirconium. Which is typically used as cladding for nuclear fuel rods. Something that a fair portion of the world would freak out about, because anything that's good for nuclear must be bad. Plus there's this gem: https://en.wikipedia.org/wiki/...

Re:Probably not useful

[Plazmid]

Current jet turbine blades(at least the first stage ones) are made of some of the most exotic materials we know of using some pretty expensive manufacturing processes. First stage jet turbine blades are almost always made of single crystalline super alloy. Oh and they're hollow, so they have to be made from a crazy investment mold. Oh and tiny holes have to be EDM'd into them.

It's a pretty expensive to make them, but it's worth it. All this crazy manufacturing is to done so that jet turbines can burn hotter, so that by Carnot they're more efficient. Even small changes in efficiency can be worth millions of dollars in fuel savings.

So as long as this material isn't as hard to process as ceramics(and it exists), it will probably find some use in a jet engine.

Re:Probably not useful

[Bob the Super Hamste]

Those blades also have exotic coatings and actually operate at a temperature above the melting point of the metal in them. A couple of weeks ago I heard the BBC Elements program on nickel and they were bringing up its use in jet engines. Jet turbines use the vast majority of the very limited supply (about 70% of 40 tons) of rhenium produced each year and it is one of the most expensive metals so I doubt the cost is an issue.

Re:Applications?

[TheReaperD]

With current fuels, no. However, if you can build engines with much higher melting points the options for fuels grows and you may get an engine with higher power, better fuel efficiency or both. Or you could just end up with a really expensive paper weight. That's why modern companies are so skittish about R&D.

Re:Make the stuff

[godrik]

Yeah right slashdot! Stop giving us hope for new fancy material with potential application in engineering! We only care about politics and social issues! This is slashdot, not a geek news website!

Re:Applications?

[rogoshen1]

Engineers come from all walks of life, and don't usually wear signs that say "Hello, my name is engineer". You could have been near one at the grocery store, on the bus, or in line at Starbucks. So my question is, how do you *know* for certain you aren't near an engineer, right now?

Re:Applications?

[Locke2005]

"Nowhere near an engineer"... so, you're riding in the caboose, then?

Re:Melting is for cows.

[rubycodez]

You keep milking that cheesy cow fetish whey too much.